


Purple Stained Morality

by wednesday_d



Series: Batman Undies [1]
Category: Teen Wolf (TV)
Genre: Extremely Underage, Finger Sucking, Frottage, M/M, Nipple Play, Shota!Stiles, Shotiles, stiles is eleven
Language: English
Status: Completed
Published: 2013-10-18
Updated: 2013-10-18
Packaged: 2017-12-29 17:36:55
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 4,664
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1008172
Author URL: https://archiveofourown.org/users/wednesday_d/pseuds/wednesday_d
Summary: <blockquote class="userstuff">
              <p>He’s gonna be the death of Derek, this beautiful boy, all soft curves and sharp eyes and innocent gestures. And Derek can do nothing but look on with hungry eyes and gentle hands and a breaking heart and an already broken resolve.</p>
            </blockquote>





	Purple Stained Morality

**Author's Note:**

> Thanks A BILLION to [Keri](http://letsleepingwerewolveslie.tumblr.com/) for the beta! Any remaining mistakes are my own because of course I had to go and do some last-minute changes.

Derek doesn’t have anyone to blame for this hot mess but himself. The hot mess in question could technically be avoided if—well, if he could avert his eyes and pretend he’s the embodiment of the three wise monkeys, but it’s a proven fact that when it comes to Stiles, feigning ignorance and lying to himself doesn’t really work.

It goes a bit like this: Mrs. McCall stopping on her way home for groceries and not taking any time in picking Scott’s underwear; Scott taking a look at the briefs in the package with the Batman logo emblazoned on it and saying _no_ ; Scott giving the unopened package to Stiles because geeky underwear does deserve proper recognition and appreciation in fact; and finally, Stiles showing them to Derek because _Batman underwear, look, Derek, it’s Batman, see? How cool is this, huh?_

So yeah. Stiles has a new pair of undies with the bat signal on them, one in purple and one in blue, and it’s a disaster because Stiles wants to wear them and he wants Derek to see them. And Derek is not a person that should be trusted with this, but here they are anyway, Derek slack-jawed and already half hard in his jeans and Stiles grinning with round, bright eyes filled to the brim with excitement.

So Derek sits there, on the couch in the Sheriff’s living room where he’s supposed to be watching over the Sheriff’s eleven year old kid, as Stiles runs around searching for something to open the package with. In theory, Derek maybe shouldn’t allow Stiles access to any sharp objects as the kid’s an accident waiting to happen on a good day, but right now, Derek’s feet have turned to stone and his heart into a hummingbird and great disasters would fall upon them if he were to do something as complicated as balance on his legs.

It takes all of five minutes for Stiles to stomp back downstairs from his room, this time very much not wearing clothes, except for those damned purple ( _purple!_ ) undies, of course.

Somewhere out there, there’s probably a god and it’s a cruel and mean entity that thrives on Derek’s pain.

Derek opens his mouth, to say what exactly he’s not very sure, so he closes it and clenches his jaw instead as Stiles climbs on the couch next to him.

“They’re awesome!” _Awesome_ seems to have invaded Stiles’ vocabulary for the past few weeks thanks to Scott saying it all the time, and he uses it to describe pretty much everything. Derek wouldn’t exactly say he finds this situation _awesome_ , though. “I’m Batman,” Stiles adds in a decidedly non-Batman voice and proceeds to strike a pose right in front of Derek and it would be cute if Derek wasn’t silently having an aneurysm.

It’s ridiculous. It’s confusing and annoying, but most of all it’s fucking horrible because there shouldn’t really be anything sexy about Stiles’ scrawny, soft body trying to imitate Batman’s imposing figure, but Derek’s dick doesn’t seem to have gotten the memo and it stands up in attention at the view.

It seems like a cruel joke from fate that the only part of Stiles’ body that can afford to lose some fat is his butt. It’s round and full with two delicious little dimples right above the plump cheeks and Derek thinks that if Mrs. McCall had been buying the underwear with Stiles in mind she would’ve gotten them in a bigger size because the sight in front of him is practically indecent.

Derek realizes he’s been staring for a while and Stiles’ cheeks are starting to get red in a way that speaks more of humiliation for his excitement than anything else and all pervy thoughts aside, Derek would cut off his feet before he let Stiles think he sees him as a weirdo.

“I dunno,” he manages to say in forced nonchalance, “I saw you jumping on a chair last week because of a spider.” And Derek remembers that incident only too well; Stiles had to climb over him to get to the empty chair and all he would’ve needed to do to feel Derek’s boner was to lose the death grip he had on Derek’s knees. “Maybe you need to be Robin for a bit before you’re allowed to upgrade to Batman.”

“What? No!” Stiles looks downright insulted and he puffs his cheeks and his chest and Derek refuses to move his gaze to Stiles’ pert, pink nipples that look downright biteable. Stiles bounces once on the couch and exclaims with vehemence, “Robin isn’t as cool!”

“Well…Batman is a genius and a millionaire and I know for a fact that you still have homework,” Derek says with a raised eyebrow. Stiles’ face falls and Derek really hopes he goes upstairs to put on some clothes before he does something terrible, like pulling Stiles down on his lap and groping him. No, nope, bad thoughts, abort, abort. “Your dad left a note, don’t look at me like that,” he adds because he knows that unless the Sheriff is brought into the conversation Stiles will try to find a way to slither out of any and all work he has to do.

“But it’s Saturday! You are no fun, Derek,” Stiles says with a pout. He jumps off the couch then, drags his feet towards the stairs, and it takes all of Derek’s (admirable) self-restraint not to slap Stiles’ butt as it passes in front of him.

It says a lot about his life and his luck when Stiles comes back down with all his school stuff in his arms and still wearing nothing but the damn undies.

“Are you going to do your homework in your underwear? Really?” Derek’s voice sounds strangled to his own ears but Stiles just pokes out his tongue at him and plumps down on the floor between Derek’s legs and the coffee table.

A few moments of silence pass with Stiles not moving at all and Derek has a fraction of a second to realize why before the kid turns his head and looks up to Derek with wide, soulful, puppy eyes.

“No,” Derek says instantly because whatever Stiles is about to ask, Derek probably shouldn’t do, otherwise the kid wouldn’t resort to the damn puppy eyes (another thing he’s gotten from Scott, and if anyone is interested in Derek’s opinion, Scott and Stiles spend way too much time in each other’s pockets.)

“But you do English in college, you can like, finish my report in five minutes.”

“Stiles,” he begins, wanting to sound as stern as possible, but that trembling bottom lip is sort of getting to him, even though he knows Stiles is the biggest faker to ever fake. “I’m not doing your homework for you,” he says with as much of a note of finality as he can muster.

“I hate you,” Stiles tries to sound angry, but Derek knows it never really works out for him. They had pretty much the exact same conversation when he came back for Christmas after his first semester at college and Stiles had declared that now that Derek had moved on to higher education he should do all of Stiles’ homework because it would be so easy for him.

Instead of replying, Derek just rolls his eyes as he gets off the couch and sits next to Stiles. He helps the kid stay focused on the same subject for more than five consecutive minutes and the next hour passes easily enough, despite the cold sweat that starts running down Derek’s spine and the low burn of lust that’s brewing somewhere below his stomach.

It’s all because he gets in the horrible habit of rubbing and petting the back of the boy’s neck every time Stiles gets the correct answer on the first try or makes a remark or says something insightful. Stiles, of course, doesn’t _really_ need anyone’s help when it comes to studying; he is terribly smart all on his own.

Derek’s hand practically never stops touching him.

Later, when the sun has started going down, Stiles thankfully puts on his pajamas and demands dinner which is enough of a distraction for Derek. They eat spaghetti with some pre-made canned cheese sauce in comfortable silence until Stiles starts slurping the spaghetti as obnoxiously as possible while making faces at Derek.

It’s a lost battle before it even begins; there’s nothing Derek can say that will make Stiles stop and pretending to be disgusted will only encourage Stiles to try harder. And the real problem is that Derek simply can’t turn his eyes away from where Stiles’ lips are practically having noisy sex with his dinner.

“You realize I don’t find that disgusting, right? I grew up with Laura,” Derek tells him because just staring outright at the boy’s mouth is creepy even on his scale of questionable motives. Stiles, however, doesn’t seem to care much, he just sticks his tongue at Derek and proceeds to attempt to clean his face with it.

“Oh, for crying out loud,” Derek grumbles under his breath as he gets up, grabbing a napkin and before the kid has time to react, he’s gripping the back of Stiles’ neck and cleaning his face like an actual human being should.

“Umf—D- _Derek_ —mph,” Stiles tries to protest but Derek ignores him even when the kid squeaks, “I’m not _five_ , I can do it on my own!”

“Oh yeah?” Derek retorts, “I didn’t see you using a napkin before.” He sounds frustrated and he _is_ , he’s barely holding on, but he knows it’s not fair to snap at Stiles so he forces himself to calm down, makes his touch more gentle, his face less disapproving.

When he’s finally done, Derek looks down at him, one hand still on the back of Stiles’ neck, the other on his face and God…damn it all to hell. Stiles is looking up at him with eyes wide and mouth parted, his lips cherry red and puffy and his cheeks pink from all the rubbing and Derek needs to put some space between them. He needs to take a step back and clear his head and maybe slap his own face a couple of times.

What he does instead is move his thumb to the soft curve of Stiles’ lower lip and lightly press down.

He’s pretty sure that the gasp that escapes from Stiles isn’t a figment of his depraved imagination. _Fuck_.

Without consciously deciding it, he slips his finger further into Stiles’ warm mouth, transfixed by the sight and feeling like he’s floating, a deep ache taking up residence somewhere in his stomach as the kid’s tongue caresses the tip of his thumb.

It would be so easy, so simple and just so _easy_ to unzip his jeans, guide Stiles’ pretty mouth over his cock and let him suck on the head. He knows Stiles would be a natural at it, he has witnessed the kid’s oral fixation first hand and it’s a not so well kept secret between himself, the Sheriff and Mrs. McCall that Stiles still sucks his thumb when he sleeps.

When oxygen finally gets to Derek’s brain and he escapes the time-freeze zone he has entered, he pulls his hand back and clears his throat as non-awkwardly as he can. “Uh, are you done? With the spaghetti?”

Stiles just looks at him, still frozen in the moment that Derek somehow managed to drag himself out of and Derek really has to be the responsible one here and it sucks. And not in the fun way.

“Stiles. _Stiles_ ,” he says a bit more sharply and the kid blushes crimson down to his neck and up to his ears as he shakes his head and comes out of his daze. “I’m gonna take the dishes to the sink. I’m washing, you’re drying.”

“But—” Stiles to protest, but a deal’s a deal and Stiles _has_ to help with chores, or so the Sheriff says.

Derek takes a moment to readjust his jeans in the crotch area while Stiles has his back turned to him and then they’re settling in the routine of clearing out the table.

“I hate you,” Stiles reminds him five minutes into doing the dishes. He’s standing on the small step they keep in the kitchen for this exact purpose, because Stiles is kind of short and without it, it wouldn’t really be wise for him to handle slippery glass and porcelain. “You are the worst. You should let me watch _Halloween_ for this.” It’s weak, is what it is and Derek huffs at Stiles’ pathetic attempt to guilt trip Derek. The Sheriff has a strict policy of no horror films for Stiles because he’s certain his kid is heading towards delinquency as it is and he doesn’t need the encouragement of twisted movies to take it one step further. Stiles and Scott have tried this routine, guilt tripping and bribing either Derek or Laura in letting them watch slasher films one time too many.

So Derek says a resolute _no_ and makes sure to escape the kitchen and grab the TV remote as soon as the last dish is done before Stiles can even put the dish towel in its place.

Ten seconds later and Stiles, entirely predictably, jumps at him from behind and tries to climb in his lap to steal the remote from him. “Derek, DerekDerek _Derek_ , give it to me,” Stiles whines and Derek is not above pinching and biting as much as Stiles does. Sure, he’s lusting after the kid like there’s no tomorrow—and there probably won’t be for him if anyone ever finds out—but he practically grew up with/raised Stiles, which is fucked up at best, what with the whole lusting after him, but the point is that when they fight like this, he regress back to the obnoxious kid he was when Stiles was no more than five.

“Jesus, Stiles, would you calm down?” he says exasperate after a few minutes of rolling around on the couch. It’s not like they’re any kind of match; Derek knows he could keep the kid still using just one hand, but it’s fun indulging him every now and then. “Did you have any sugar before dinner?” he asks with narrowed eyes, because Stiles after dinner is usually dead weight and this is a bit too much energy he’s demonstrating.

“No,” Stiles rolls his eyes, “you were with me all the time, how could I sneak anything past you?”

“Hmm,” Derek is not convinced, but he lets it go for now. “We are not watching _Halloween_ ,” Derek watches Stiles’ exaggerated pout with amusement and adds, “but we can watch _Hocus Pocus_ if you want for your weird Halloween fetish. Even though it’s May.”

There’s some arguing after that, but Derek can tell Stiles does it mostly out of habit so it’s not long before they’re lining up the movie and settling down.

Ten minutes in and Stiles has found his way right up next to Derek. Fifteen minutes after that he’s crawled under Derek’s arm. Half way into the movie, Derek dares to look down and finds the kid practically balled up against his chest, eyes half closed and one hand suspiciously close to that perpetually half open mouth of his.

Derek moves his hand to Stiles’s head, tousling his hair lightly. “Tired?” he asks.

“No,” Stiles says slowly, but it’s obvious that he’s not even paying attention. It’s as much adorable as it is worrying. Stiles has an appointment next Thursday with a doctor; the last couple of months have apparently been hell in school, his teachers saying he can’t keep his focus for more than a few minutes and he has these bouts of excessive energy that leave him half asleep after. It also doesn’t help that he spent the morning running around with Scott before Mrs. McCall came (along with those damn new underwear) to pick her son up.

It’s a stupid thing to do and it will lead nowhere good, Derek knows, but he can’t really help the way his hand slides down so that his arm is wrapped all the way around the boy. Stiles _hmm_ s and burrows his face against Derek’s chest for a moment before turning back to the TV where the witches are having a mild freak out about kids in Halloween costumes.

It doesn’t take long for his hand to develop a mind of its own and soon Derek is dragging the flat of his palm up and down over Stiles’ chest. It’s too slow, too deliberate and focused to be called a caress and one day, Derek will probably have to ask a doctor about the dangers of blue balls because he has been on and off hard for the entire day and it’s getting to the point where he has half a mind to get up and go jerk off in the bathroom as his cock swells up yet again.

It’s not going to happen, though. The way Stiles’ body is turned towards him, the way he can feel the boy’s every breath as his chest moves under Derek’s hand, the feel of the fingers of his left hand as they curl and uncurl over Derek’s stomach…Derek is not willing to give this up now, no matter what dangerous territory he’s in.

He has his eyes resolutely glued to the screen but he’s not seeing a single damn thing because he’s acutely aware of Stiles’ eyes moving to his face every ten seconds or so and it’s not just because he can feel the slight movement of his head as it turns up to him. Stiles’ gaze is like an electric current he’s pretending to ignore.

Derek is trying so hard to convince himself to stay focused on the movie and not on Stiles that it takes him a long time to catch up to the fact that Stiles’ breathing has gotten heavier, his exhales almost shaky. And as soon as he tunes in he realizes that he has been rubbing the kid’s left nipple over the thin material of his t-shirt for the past few minutes.

Jesus Christ. He squeezes his eyes shut for a second and thinks _don’t look down, down look down, don’t look down_ , but he doesn’t stop the movement of his hand, doesn’t sit up straighter, doesn’t push Stiles away.

He can feel how Stiles’ nipple has gone stiff under his ministrations and he applies more pressure over the tight nub and he’s rewarded with a soft gasp.

There’s a hot piece of ember lodged somewhere in his belly and Derek is burning from the inside out. Every point of contact between him and the boy is branding his skin and is making him sweat under his arms, around the collar of his t-shirt where he feels like he’s choking, on his temples where his pulse is out of control and between his legs where his erection is making him dizzy with the need to touch, find friction and just _take_.

The choice of what happens next is taken out of his hands when Stiles lifts his leg and drapes it over his thighs, his hand grabbing a handful of Derek’s shirt for balance. When Stiles’ hips make the tiniest of rolls Derek almost gasps with the feel of something hard making contact with the outside of his thigh.

So Stiles is hard. Stiles has an erection, caused by Derek nonetheless, and he’s rubbing it against Derek.

It’s impossible not to look down, then, to acknowledge what he has done and Derek thinks he might be falling into some kind of deep abyss with how dizzy he feels.

Those bright eyes of Stiles’ he loves so much are now closed tight, his brow furrowed in concentration and his mouth is open as he pants unsteadily against Derek’s chest.

Derek can’t help but trail his hand further down to the hem of the t-shirt Stiles has on and slip his fingertips tentatively against warm skin. Stiles reacts almost instantly, breath hitching and hips bucking against Derek, rubbing his cock, still small and slender even though it’s hard and fuck if Derek doesn’t somehow get a kick out of this, through the materials of their clothing and letting out a soft whimper.

Emboldened by Stiles’ reactions and desperate, so damn desperate and hungry for more, Derek pushes his hand fully under the t-shirt and brings it back up again to the tender nipple he was playing with earlier.

There’s a part of him that wants to push the kid back, take his shirt off in order to put his mouth on Stiles’ chest, lick and bite at those sensitive nipples, scratch that narrow chest with his blunt nails, but he’s afraid it will break whatever spell they’re caught in, maybe overwhelm Stiles enough to make him turn away from Derek.

Instead, he pinches lightly at where Stiles seems to have swollen up from all the teasing before, passes his thumb over and over across the tender skin until his nipple is pert again. He cups his hand over the area and squeezes like he would with a girl and Stiles jerks, lets out something between a hiccup and a sob and Derek brings his other hand up, pushes his middle and forefinger in Stiles’ mouth, gives him something to suck on.

It’s enrapturing how his lips, shiny, wet and so lush, work around his fingers. He thrusts them in and out a couple of times and just like that, Stiles comes, twitching and shaking, so incredibly pretty right there in his arms.

When the boy finally opens his eyes and looks up to Derek, his eyelashes are wet and his eyes are sparkling even if they’re still a bit cloudy. His mouth parts on a sigh and Derek’s cock twitches at the way his fingers tug on the lower lip as he pulls them slowly out.

He cups Stiles’ cheek, flushed pink and so soft beneath his palm, and uses his thumb to rub soothingly over his cheekbone while his other hand is caressing slowly, absentmindedly Stiles’ stomach.

He’s gonna be the death of Derek, this beautiful boy, all soft curves and sharp eyes and innocent gestures. He watches as Stiles slowly nods off, breath coming slower, deeper. When he’s sure Stiles is out of it, he stands up carefully and picks him up from the couch. The trip up to Stiles’ room is a trial in and of its own, because while the kid is light as a feather in his arms, Derek’s still hard and in need of release, preferably five minutes ago.

For some reason, taking off Stiles’ pants and undies makes him feel like more of a creeper than usual. It’s probably the fact that he still wants to touch Stiles, explore his body for as long as he can even though Stiles is sleeping. But he keeps his hands to himself and just puts him in his pajamas again without bothering with underwear; he really can’t trust himself right now.

He pulls up the sheet over the kid’s prone body, leans down to press a light kiss to his temple and leaves the room as quietly as he can. He has a moment of insanity where he thinks about keeping those stupid purple underwear drenched in Stiles’ thin come, but he just puts them in the laundry basket instead. Stiles would know if they went missing.

Once back downstairs, he takes a look at the clock, figures he has about half an hour before the Sheriff comes home and decides that he will die before he manages to hold off until he’s back home in his own bedroom.

So Derek makes a beeline for the downstairs bathroom, locks the door and unzips his jeans, _finally_ , over the toilet.

The moment his fist closes around his cock he knows this will be quick. All he thinks about is how Stiles had felt under his hands, recalls little details like the goosebumps that run down his side when Derek first touched his fingertips on Stiles’ ribs, the way his back bowed when he clumsily tried to find friction against Derek.

He wonders if Stiles hadn’t been so tired if he would’ve lasted longer; long enough for Derek to run his hand down Stiles’ back; long enough to cup his bubble butt and press him flat against him. Maybe he would have teased his fingertips over those delicate dimples, pinching the supple flesh there, then slide his pinky under the waistband of the pajamas.

“Shit,” Derek curses lowly, his strokes becoming more erratic as precome starts sliding down his shaft from the slit in a steady stream, a sure sign he’s very close. Each tug at his cock is slicker now, easier and yet harder because he’s practically trembling, thinking of how the fingers around his dick had been in Stiles’ mouth not fifteen minutes ago.

He closes his eyes, thinks of how his fingers, wet from the boy’s own spit, could slide down the back of his underwear, along Stiles’ delicious crack and dip lower, deeper until he pushed them against the boy’s tight, little hole-

“ _Fuck_ ,” Derek comes with a whole body shudder, white stripes of come shooting in the toilet, getting his fingers and palm messy, just like Stiles’ undies had been and at the thought he seizes, another spurt of come valiantly shots out of his nearly spent cock.

He breathes in and out a few times, blinks until he stops seeing white spots and then turns to grab the toilet paper and clean himself up.

It’s torture waiting up for Stiles’ dad to come home. He tries watching the end of _Hocus Pocus_ , but he can’t focus, can’t get his hands to stop shaking with the need to go upstairs and touch Stiles, maybe lie down next to him, curl his body around the boy’s much smaller one and bury his nose in the silky strands of hair on the back of his neck.

When the Sheriff finally arrives, Derek doesn’t have the energy to even feel uncomfortable. It’s scary and unsettling how easy it is to make eye contact and reassure him that no, Stiles wasn’t too much of a menace and that he’s sure he won’t be joining them for lunch the following day. Laura is coming back into town from her long trip and they are spending the day with each other, but they’ll make sure they all have dinner together on Monday.

He doesn’t know what happens from here on. Tomorrow night he’s going out with Laura and they’ll probably end up in one of the dives Erica always seems to drag them to and he’ll probably try to find someone. It’s a practiced move, go out, try to flirt, try to dance or make out with some nameless dude or girl, but no one so far has managed to catch his attention and take his mind off of the sweet little boy living next door to him. It’s been more than a year since the last time he kissed and touched someone without being plagued by images and thoughts of Stiles.

No one ever seems right; guys are always too hard, too sure of themselves; girls too deliberately sensual and too curvy. But he’ll look all the same, _try_ all the same, in hopes that this will be the night he finally gets Stiles out of his mind and out from underneath his skin.

But he knows, he already knows that come Monday, his eyes will still linger on the boy, his hands will still itch with the need to make contact, his lips will still tingle with the need to taste. What he doesn’t know, this time, is if Stiles will have finally caught on and whether he’ll turn away from him or come seeking more.

**Author's Note:**

> There might, possibly be a sequel; if I ever get around to putting into words what I know happens next.


End file.
